Comparative histological and histochemical study of the Jalapa root

Abstract

A comparative histological and histochemical study was carried out in samples of ''Jalapa root'' complex which includes three species of lpomoea, I. purga (Wenderoth) Hayne, I. orizabensis (Pelletan) Steud, and I. jalapa (L) Pursh. Stains with PAS, Red Oil, Naphthol Blue Black and IKI, were performed with samples of roots of this complex. The main histological differences between the three species were found in the cork, in the form, distribution and abundance of the laticifers. The size, number and distribution of the xylem, phloem and fibers, also were important characteristics of each species as well as the presence of brachysclereids and the abundance of druses. The special stains helped to identify some cells or cell structures.